How does CT work?

The scanning part of a CT machine consists of an X-ray tube and a number of detectors to collect information.The X-ray beam scans the selected level, and its intensity is absorbed and attenuated accordingly due to its interaction with tissues of different densities. The detector converts the collected X-ray signals to electrical signals, which are converted to digital signals by an analog-to-digital converter (A/D converter) and fed into a computer to be stored and processed, thus obtaining the CT number of each unit of volume at that level and arranging it into a digital matrix (Figure 7-2). These figures can be stored in the hard disk (Hard disk), floppy disk (Floppy) and magnetic tape (Magnetic tape, MT), can also be printed with a printer. The digital matrix is converted to an image on a monitor by a digital/analog (D/A) converter, which is a cross-sectional image of the layer. The image can be captured on film with multiple cameras for reading, archiving, and consultation.